Note: Descriptions are shown in the official language in which they were submitted.
Attorney Ref.: 1147P079CA01
TITLE
STIMULATION DEVICE ADAPTER
[0001] [This paragraph is intentionally left blank.]
FIELD OF THE INVENTION
[0002] The invention relates generally to tissue identification and integrity
testing, and more
particularly to systems and methods for safeguarding against nerve and muscle
injury during
surgical procedures, location and stimulation of nerves and muscles,
identification and
assessment of nerve and muscle integrity following traumatic injuries, and
verification of range
of motion and attributes of muscle contraction during reconstructive surgery.
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BACKGROUND OF THE INVENTION
[0003] Even with today's sophisticated medical devices, surgical procedures
are not risk-free.
Each patient's anatomy differs, requiring the surgeon to be ever vigilant to
these differences so
that the intended result is accomplished. The positioning of nerves and other
tissues within a
human or animal's body is one example of how internal anatomy differs from
patient to patient.
While these differences may be slight, if the surgeon fails to properly
identify one or several
nerves, the nerves may be bruised, stretched, or even severed during an
operation. The negative
effects of nerve damage can range from lack of feeling on that part of the
body to loss of muscle
control.
[0004] Traumatic injuries often require surgical repair. Determining the
extent of muscle and
nerve injury is not always possible using visual inspection. Use of an intra-
operative stimulator
enables accurate evaluation of the neuromuscular system in that area. This
evaluation provides
valuable knowledge to guide repair/reconstructive surgery following traumatic
injury, and when
performing a wide range of surgeries.
[0005] It may be desirable for diagnostic and/or therapeutic reasons to
differentiate and/or
identify within a tissue region the presence of targeted sympathetic nerves
and/or
parasympathetic nerves. Further, it may be desirable to target specific nerves
and tissue regions
and limit stimulation to the targeted areas.
SUMMARY OF THE INVENTION
[0006] The invention provides devices, systems, and methods for intra-
operative stimulation that
enable accurate evaluation of the neuromuscular system to guide repair or
reconstructive surgery.
[0007] One aspect of the invention provides devices, systems, and methods
comprising a tissue
stimulation system having a housing having a proximal end and a distal end, an
operative
element having an electrically conductive surface sized and configured for
electrical stimulation
of a targeted tissue region, and the operative element extends from the
proximal end of the
housing. The housing proximal end may comprise an operative element adjustment
portion to
allow movement of the operative element, with the electrical stimulation being
in the form of a
stimulation signal having an amplitude and a duration for providing a first
indication. A
stimulation control device is electrically coupled to the operative element,
the stimulation control
device comprising a power source and stimulation signal generating circuitry.
The tissue
stimulation system may conform to the IPX1 water ingress standard.
[0008] In one aspect of the invention, the stimulation control device is
positioned within the
housing. The housing may comprise a gripping base portion and the operative
element
adjustment portion. The operative element adjustment portion comprises a
flexible nose cone.
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[0009] The first indication comprises a visual indication located on the
housing, and the housing
may be tubular. The visual indication may also include a reflective element.
The visual
indication may comprise an illuminating circumferential ring indicator, the
illuminating
circumferential ring indicator being visible around the circumference of the
tubular housing.
[0010] Yet another aspect of the invention provides devices, systems, and
methods comprising a
tissue stimulation system comprising a housing, such as a tubular shaped
housing, having a
proximal end and a distal end, an operative element having an electrically
conductive surface
sized and configured for electrical stimulation of a targeted tissue region,
the operative element
extending from the proximal end of the housing, and wherein the electrical
stimulation is in the
form of a signal having an amplitude and a duration for providing a first
indication to the user of
close proximity of the operative element to the targeted tissue region, and a
stimulation control
device electrically coupled to the operative element, the stimulation control
device comprising
stimulation signal generating circuitry. The housing may include a first
control device for turning
the stimulation signal to the operative element on and off and for providing
adjustment of the
stimulation signal amplitude, the first control device being electrically
coupled to the stimulation
control device. The housing may also include a second control device for
providing adjustment
of the stimulation signal duration, the second control device being
electrically coupled to the
stimulation control device.
[0011] Additional aspects of the invention provide a tissue stimulation system
that may be
sterilized using ethylene oxide, for example, and prepackaged for single use.
The stimulation
signal of the tissue stimulation system includes an amplitude that may range
between about zero
milliamps and about 20 milliamps, allowing for accurate selective stimulation
of both muscles
and nerves, and also identification of nerves and muscles, muscle attachments,
or to contract
muscles to assess the quality of surgical interventions. The tissue
stimulation signal duration may
include a range between about zero microseconds and about 200 microseconds,
for example. The
first indication provided by the tissue stimulation system may include, for
example, audio and
visual indications. The tissue stimulation system may further include a second
indication means
to provide confirmation of power on to the device and delivery of a
stimulation signal to the
electrically conductive surface. The first and second indication means may be
combined into a
single indication means. The operative element of the tissue stimulation
system may comprise a
probe, for example, where the electrically conductive surface of the probe
comprises between
about 1 millimeter and about 10 millimeters of the proximal end of the probe,
and the probe
comprises a diameter between about 0.5 millimeters and about 1.5 millimeters.
The tissue
stimulation system may also further include a return electrode electrically
coupled to the
stimulation control device.
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[0012] Additional aspects of the invention provide a tissue stimulation
system, such as a medical
device comprising a housing having a proximal end and a distal end, the
housing sized and
configured to be held by a user in either the left or right hand, a probe
having an electrically
conductive surface sized and configured for electrical stimulation of a
targeted tissue region, the
probe extending from the proximal end of the housing. The housing proximal end
may comprise
a probe adjustment portion to allow movement of the probe. The electrical
stimulation is in the
form of a signal having an amplitude and a duration for providing a physical
motor response, a
stimulation control device electrically coupled to the probe and sized and
configured to be
positioned within the housing, the stimulation control device comprising
stimulation signal
generating circuitry. The housing may include a first control device for
turning the stimulation
signal to the probe on and off and for providing adjustment of the stimulation
signal amplitude,
the first control device being electrically coupled to the stimulation control
device. The housing
may also include a second control device for providing adjustment of the
stimulation signal
duration, the second control device being electrically coupled to the
stimulation control device.
[0013] According to another aspect of the invention, a stimulation control
device electrically
coupled to at least one surgical tool, which can comprise, e.g., a cutting,
grasping, drilling,
screwing, and/or viewing tool. The application of stimulation voltage or
current to the device
allows the clinician to observe muscle contraction or changes in the nervous
system response
when the surgical tool is in close proximity to viable nerve or muscle tissue.
The surgical tool
thus becomes a neural/muscular stimulating electrode. In use, different
surgical tools,
individually deployed in association with different medical procedures, can
make use of a singe,
stimulation control device, to which a selected surgical tool can be
temporarily coupled for use.
[0014] According to yet another aspect of the invention, the stimulation
control device may be
embedded within the surgical tool to provide a medical device capable of
providing stimulation,
as described above.
[0015] Another aspect of the invention provides devices, systems, and methods
comprising a
stimulation monitor or probe and at least one electrode. In one embodiment, a
hand held
stimulation probe or monitor includes the stimulation control device and at
least one stimulation
electrode within a unified housing to provide an ergonomic stimulation device.
The hand held
stimulation probe can be a sterile, single use instrument intended for use
during surgical
procedures to identify nerves and muscles, muscle attachments, or to contract
muscles to assess
the quality of surgical interventions or the need for surgical interventions,
or to evaluate the
function of nerves already identified through visual or audible means, or by
other nervous system
monitoring instruments.
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[0016] Yet another aspect of the invention provides devices, systems, and
methods, including a
method of testing a tissue region of a patient that includes providing a
tissue stimulation system
having an operative element extending from a proximal end of a housing, the
housing proximal
end may comprise an operative element adjustment portion to allow movement of
the operative
element, moving a first control device to an activation position causing a
stimulation signal to be
generated by the stimulation system and transmitted to the operative element,
engaging the
patient with the operative element at a targeted tissue region, and observing
the targeted tissue
region for a first indication.
[0017] The method may further include engaging the patient with a second
electrode which is
electrically coupled to the stimulation system, the second electrode allowing
the stimulation
signal to flow from the operative element, through the patient's body to the
second electrode, and
back to the stimulation system.
[0018] Another aspect of the invention provides devices, systems, and methods
comprising a
hand held tissue stimulation apparatus including a tubular shaped housing
comprising a gripping
base portion and an operative element adjustment portion, the gripping base
portion comprising a
first housing element and a second housing element, a stimulation control
device positioned
within the gripping base portion, a battery positioned within the gripping
base portion and
coupled to the stimulation control device to provide power to the stimulation
control device, a
visual indication coupled to a proximal end of the gripping base portion, the
visual indication
comprising an illuminating circumferential ring indicator, the illuminating
circumferential ring
indicator being visible around the circumference of the tubular housing, and
an operative
element having an electrically conductive surface sized and configured for
electrical stimulation
of a targeted tissue region, the operative element being coupled to the
stimulation control device
and extending from the proximal end of the operative element adjustment
portion.
[0019] The operative element adjustment portion may comprise a flexible nose
cone sized and
configured to allow movement of the operative element, and the visual
indication further
includes a reflector element. A return electrode electrically may be coupled
to the stimulation
control device.
[0020] According to yet another aspect of the invention, a kit of devices
provides tissue
stimulation to a targeted tissue region. The kit may include a hand held
stimulation probe
including a housing sized and configured to be held with either a left or
right hand, the
stimulation probe being sterilized and disposable, and including an operative
element extending
from a proximal end of the housing, the housing proximal end may comprise an
operative
element adjustment portion to allow movement of the operative element, a lead
including a
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return electrode coupled to the stimulation probe, and instructions for use
describing the
unpacking and tissue contact procedure for the stimulation probe.
[0021] Additional aspects of the invention provide a stimulation control
device electrically
coupled to a tissue cutting instrument, or a stimulation control device
electrically coupled to a
drilling instrument, or a stimulation control device electrically coupled to a
pilot auger for hard
surface rotary probing prior to pilot hole drilling, or a stimulation control
device electrically
coupled to a fixation device, which is commonly used in spinal stabilization
procedures and
internal bone fixation procedures.
[0022] In another aspect, the invention provides a first device for generating
and applying a
stimulation current to tissue. The devices, systems, and methods also include
a second device for
sensing the presence or absence of an anticipated physiologic response to the
application of the
electrical stimulation current. The presence of the anticipated physiologic
response indicates the
innervation of targeted nerve fibers or branches within the tissue region.
Once differentiated and
identified, the targeted nerve fibers or branches can be manipulated to
achieve desired diagnostic
and/or therapeutic outcomes.
[0023] The devices, systems, and methods are well suited, e.g., for
differentiating and/or
identifying localized branches of the vagus nerve. The vagus nerve runs from
the brain through
the face and thorax to the abdomen. It is a mixed nerve that contains
parasympathetic fibers. The
vagus nerve has the most extensive distribution of the cranial nerves. Its
pharyngeal and
laryngeal branches transmit motor impulses to the pharynx and larynx; its
cardiac branches act to
slow the rate of heartbeat; its bronchial branch acts to constrict the
bronchi; and its esophageal
branches control involuntary muscles in the esophagus, stomach, gallbladder,
pancreas, and
small intestine, stimulating peristalsis and gastrointestinal secretions.
Being able to differentiate
and/or identify the presence of a branch of the vagus nerve within a given
tissue region within
the body makes possible the development and application of diverse diagnostic
and/or
therapeutic techniques for parasympathetic mediation of a diverse number of
anatomic functions,
e.g., in the digestive system, the respiratory system, or the heart.
[0024] For example, one aspect of the invention provides devices, systems, and
methods that
make possible the differentiation and identification of the epicardial fat
pads on the surface of the
heart, which are innervated by parasympathetic vagal nerve fibers. The
devices, systems, and
methods thereby make it possible to access the parasympathetic nervous system
of the heart for
therapeutic benefits, such as to control the ventricular rate or to provide
physiologic control of
the AV nodal rate.
[0025] Another aspect of the invention provides systems and methods for
treating a heart
comprising locating a fat pad region on a heart innervated by parasympathetic
nerves -using a
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Attorney Ref.: 1147P079CA01
first device for generating and applying a stimulation current, and then
manipulating the
parasympathetic nervous system of the heart in the region of the fat pad for
diagnostic or
therapeutic benefit.
[0026] In an embodiment, the an adapter is provided. The adapter may be
configured to connect
to the stimulation control device. The adapter may be a bipolar adapter
arranged to connect to the
housing of the stimulation device. The adapter may include a clip having a
first channel configured
to receive an operative element therein and a second channel having a return
operative element
therein. The return operative element is in electrical communication with an
electrical circuit of
said stimulation control device.
[0027] In an embodiment, the adapter may be a percutaneous adapter comprising
a connector
configured to connect to an operative element of a stimulation device and a
lead wire connected
to the connector. A needle may be connected to the lead wire to deliver a
electrical stimulation
signal to a target tissue located beneath the skin of a subject patient.
[0027a] In another embodiment, this document discloses a bipolar adapter
comprising: a clip
arranged to connect to a stimulation control device, the clip comprising: a
first channel configured
to receive an operative element therein; and a second channel; a return
operative element
positioned within the second channel; and wherein the return operative element
is in electrical
communication with an electrical circuit of said stimulation control device.
[0027b] In another embodiment, this document discloses a stimulation system
comprising: a
stimulation control device comprising: a housing; and an operative element
extending from said
housing; a bipolar adapter connected to said stimulation control device
comprising: a clip having
a first channel and a second channel; and a return operative element
positioned within said
second channel; and wherein said operative element is positioned within said
first channel.
[0028] Features and advantages of the inventions are set forth in the
following Description and
Drawings, as well as the appended description of technical features.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a diagrammatic view of a system usable in association with a
family of different
monitoring and treatment devices for use in different medical procedures.
[0030] FIG. 2 is a perspective view showing an exemplary embodiment of the
system shown in
FIG. 1, the stimulation control device being removably coupled to a
stimulation probe, and
showing the stimulation signal path through the system.
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[0031] FIG. 3A is a side view with a portion broken away and in section
showing the stimulation
probe having the stimulation control device embedded within the stimulation
probe.
[0032] FIG. 3B is a side view with a portion broken away and in section
showing the stimulation
probe having the stimulation control device embedded within the stimulation
probe, and showing
an optional needle-like return electrode.
[0033] FIG. 3C is a side view with a portion broken away and in section
showing an additional
embodiment of the stimulation probe having a housing that includes a gripping
base and a flexible
nose cone, and an illuminating ring indicator.
[0034] FIG. 4A is a side view of the stimulation probe of FIG. 3c, showing the
users hand in a
position on the stimulation probe to move the flexible nose cone.
[0035] FIG. 4B is a side view of the stimulation probe of FIG. 4A, showing the
users hand flexing
the flexible nose cone.
[0036] FIG. 5 is a side view with a portion broken away and in section showing
elements of the
flexible nose cone, the ring indicator, and the gripping base.
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[0037] FIG. 6 is a graphical view of a desirable biphasic stimulus pulse
output of the stimulation
device.
[0038] FIG. 7 is a view showing how the geometry of the stimulation control
device shown in
FIG. 2 aids in its positioning during a surgical procedure.
[0039] FIG. 8 is a block diagram of a circuit that the stimulation control
device shown
throughout the Figs. can incorporate.
[0040] FIGS. 9A and 9B are perspective views showing the stimulation control
device in use
with a cutting device.
[0041] FIGS. 10A and 10B are perspective views showing the stimulation control
device in use
with a drilling or screwing device.
[0042] FIGS. 11A and 11B are perspective views showing the stimulation control
device in use
with a pilot auger device.
[0043] FIGS. 12A and 12B are perspective views showing the stimulation control
device in use
with a fixation device.
[0044] FIG. 13 is a plane view of a kit used in conjunction with the
stimulation probe shown in
FIG. 3C, and including the stimulation probe and instructions for use.
[0045] FIG. 14 is a perspective view of the stimulation probe shown in FIG.
3C.
[0046] FIG. 15 is an exploded view of the stimulation probe shown in FIG. 14.
[0047] FIG. 16 is a diagrammatic view of a system for differentiating and/or
identifying tissue
regions locally innervated by targeted nerves.
[0048] FIG. 17A is side view of a device used in conjunction with the system
shown in FIG.
for generating and applying a stimulation current to tissue in the region of
the targeted nerve
fiber or branch.
[0049] FIG. 17B is side view of an alternative embodiment of the device shown
in FIG. 2A, and
having separate amplitude and duration selection switches.
[0050] FIG. 18A is an enlarged view of one embodiment of a bipolar electrode
array that the
device shown in FIGS. 17A or 17B may carry at its distal end.
[0051] FIG. 18B is an enlarged view of an additional embodiment of a bipolar
electrode array
that the device shown in FIGS. 17A or 17B may carry at its distal end.
[0052] FIG. 18C is an enlarged view of an additional embodiment of a bipolar
ring electrode
array that the device shown in FIGS. 17A or 17B may carry at its distal end.
[0053] FIG. 19 is a representative view of a clinician manipulating the device
shown in FIG,
17A in association with the system shown in FIG. 16.
[0054] FIG. 20 is an anatomic posterior view of a human heart, showing the
location of fat pads
innervated by parasympathetic nerves that, when accessed, can provide
therapeutic benefits.
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[0055] FIGS. 21 and 22 are diagrammatic views of use of the system shown in
FIG 16 for
differentiating and/or identifying a fat pad tissue region that is locally
innervated by
parasympathetic nerves.
[00561 FIG. 23 is a stimulation device connected to a bipolar adapter.
[0057] FIG. 24 is a bipolar adapter connector.
[0058] FIG. 25 is a front view of a bipolar connector adapter.
[00591 FIG. 26 is a bipolar adapter connector connected to a stimulation
device.
[0060] FIG. 27 is a bipolar adapter connected to a stimulation device with
clips.
[0061] FIG. 28 is a bipolar adapter having a unitary clip.
[0062] FIG. 29 is unitary clip.
[0063] FIG. 30 is a percutaneous adapter,
[0064] The invention may be embodied in several forms without departing from
its spirit or
essential characteristics. The scope of the invention is defined in the
appended claims, rather
than in the specific description preceding them. All embodiments that fall
within the meaning
and range of equivalency of the claims are therefore intended to be embraced
by the claims.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0065] This Specification discloses various systems and methods for
safeguarding against nerve,
muscle, and tendon injury during surgical procedures or confirming the
identity and/or location
of nerves, muscles, and tendons and evaluating their function or the function
of muscles
enervated by those nerves. The systems and methods are particularly well
suited for assisting
surgeons in identification of nerves and muscles in order to assure nerve and
muscle integrity
during medical procedures using medical devices such as stimulation monitors,
cutting, drilling,
and screwing devices, pilot augers, and fixation devices. For this reason, the
systems and
methods will be described in the context of these medical devices.
[0066] The systems and methods desirably allow the application of a
stimulation signal at
sufficiently high levels for the purposes of locating, stimulating, and
evaluating nerve or muscle,
or both nerve and muscle integrity in numerous medical procedures, including,
but not limited to,
evaluating proximity to a targeted tissue region, evaluating proximity to a
nerve or to identify
nerve tissue, evaluating if a nerve is intact (i.e., following a traumatic
injury) to determine if a
repair may be needed, evaluating muscle contraction to determine whether or
not the muscle is
innervated and/or whether the muscle is intact and/or whether the muscle is
severed, and
evaluating muscle and tendon length and function following a repair or tendon
transfer prior to
completing a surgical procedure.
[0067] Still, it should be appreciated that the disclosed systems and methods
are applicable for
use in a wide variety of medical procedures with a wide variety of medical
devices. By way of
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non-limiting example, the various aspects of the invention have application in
procedures
requiring grasping medical devices and internal viewing devices as well.
I. Overview of the System
[0068] FIG. 1 shows an illustrative system 20 for locating and identifying
tissue and
safeguarding against tissue and/or bone injury during surgical procedures. In
the illustrated
embodiment, the system 20 is configured for locating, monitoring, and
stimulating tissue and
other structures throughout the body. The system 20 includes a stimulation
control device 22
operating individually or in conjunction with one or more of a family of
stimulating medical
devices including, for example, a stimulation monitor or probe 100, a cutting
device 200, a
drilling or screwing device 300, a pilot auger 400, and a fixation device 500.
[0069] In an exemplary embodiment, and as can be seen in FIG. 2, the
stimulation control device
22 functions in the system 20 to generate an electrical stimulation signal 29.
The stimulation
signal 29 flows from the stimulation control device 22 through a lead 24 to a
medical device
(e.g., stimulation probe 100). The stimulation signal 29 then flows through a
predefined insulated
path 124 within the stimulation probe 100 and to an operative element, such as
an electrically
conductive surface, i.e., a coupled electrode 110. The electrode 110 is to be
positioned on or near
a region of a patient to be stimulated. In monopolar operation, a return
electrode (or indifferent
electrode) 38 provides an electrical path from the body back to the control
device 22. The
stimulation control device 22 may operate in a monopolar or bipolar
configuration, as will be
described in greater detail later.
[0070] The stimulation signal 29 is adapted to provide an indication or status
of the device. The
indication may include a physical motor response (e.g., twitching), and/or one
or more visual or
audio signals from the stimulation control device 22, which indicate to the
surgeon the status of
the device, and/or close proximity of the electrode 110 to a nerve, or a
muscle, or a nerve and a
muscle. The stimulation control device may also indicate to the surgeon that
the stimulation
control device is operating properly and delivering a stimulus current.
11. Medical Devices
[0071] The configuration of the stimulating medical devices that form a part
of the system can
vary in form and function. Various representative embodiments of illustrative
medical devices
will be described.
A. Stimulation Probe
[0072] FIGS. 3A to 3C show various embodiments of a hand held stimulation
monitor or probe
50 for identification and testing of nerves and/or muscles during surgical
procedures. As shown,
the stimulation probe 50 may accommodate within a generally tubularly housing
112 the
electrical circuitry of a stimulation control device 22. The stimulation probe
50 is desirably an
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ergonomic, sterile, single use instrument intended for use during surgical
procedures to identify
nerves and muscles, muscle attachments, or to contract muscles to assess the
quality of surgical
interventions or the need for surgical interventions, or to evaluate the
function of nerves already
identified through visual means. The stimulation probe 50 may be sterilized
using ethylene
oxide, for example.
[0073] The stimulation probe 50 is preferably sized small enough to be held
and used by one
hand during surgical procedures, and is ergonomically designed for use in
either the left or right
hand. In a representative embodiment, the stimulation probe 50 may have a
width of about 20
millimeters to about 30 millimeters, and desirably about 25 millimeters. The
length of the
stimulation probe 50 (not including the operative element 110) may be about 18
centimeters to
about 22 centimeters, and desirably about 20 centimeters. The operative
element 110 may also
include an angle or bend to facilitate access to deep as well as superficial
structures without the
need for a large incision. The operative element 110 will be described in
greater detail later. A
visual or audio indicator 126 incorporated with the housing 112 provides
reliable feedback to the
surgeon as to the request and delivery of stimulus current.
[0074] In one embodiment shown in FIGS. 3C and 14, the stimulation probe 50
includes a
housing 112 that comprises a gripping base portion 60 and an operative element
adjustment
portion 62. The operative element 110 extends from the proximal end of the
adjustment portion
62. In order to aid the surgeon in the placement of the operative element 110
at the targeted
tissue region, the adjustment portion, as will be described as a nose cone 62,
may be flexible.
This flexibility allows the surgeon to use either a finger or a thumb
positioned on the nose cone
62 to make fine adjustments to the position of stimulating tip 111 of the
operative element 110 at
the targeted tissue region (see FIGS. 4A and 4B). The surgeon is able to grasp
the gripping base
60 with the fingers and palm of the hand, and position the thumb on the nose
cone 62, and with
pressure applied with the thumb, cause the stimulating tip 111 to move while
maintaining a
steady position of the gripping base portion 62. This flexible nose cone 62
feature allows precise
control of the position of the stimulating tip 111 with only the movement of
the surgeon's thumb
(or finger, depending on how the stimulating probe is held).
[0075] The flexible nose cone 62 may comprise a single element or it may
comprise at least an
inner portion 64 and an outer portion 66, as shown in FIG. 5. In order to
facilitate some
flexibility of the proximal portion 114 of the stimulation probe 50, the inner
portion 64 of the
nose cone 62 may be made of a thermoplastic material having some flexibility.
One example
may be LUSTRAN® ABS 348, or similar material. The outer portion 66 may
comprise a
softer over molded portion and may be made of a thermoplastic elastomer
material having some
flexibility. One example may be VERSAFLEX.TM. OM 3060-1 from GLS Corp. The
nose cone
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62 is desirably generally tapered. For example, the nose cone 62 may be
rounded, as shown in
FIGS. 3A and 3B, or the nose cone may be more conical in shape, as shown in
FIG. 3C.
[0076] The nose cone 62 may also include one or more features, such as ribs or
dimples 72, as
shown in FIG. 14, to improve the gripping, control, and stability of the
stimulation probe 50
within the surgeon's hand.
[0077] The gripping base portion 60 of the housing 112 may also include an
overmolded portion
68. The overmolded portion 68 may comprise the full length of the gripping
base portion 60, or
only a portion of the gripping base 60. The soft overmolded portion 68 may
include one or more
features, such as dimples or ribs 70, as shown, to improve the gripping,
control, and stability of
the stimulation probe 50 within the surgeon's hand. The overmolded portion 68
may comprise
the same or similar material as the thermoplastic elastomer material used for
the outer portion 66
of the flexible nose cone 62.
[0078] In one embodiment, the stimulation probe 50 includes a housing 112 that
carries an
insulated lead 124. The insulated lead 124 connects the operative element 110
positioned at the
housing's proximal end 114 to the circuitry 22 within the housing 112 (see
FIG. 3A). It is to be
appreciated that the insulated lead is not necessary and the operative element
110 may be
coupled to the circuitry 22 (see FIG. 3C). The lead 124 within the housing 112
is insulated from
the housing 112 using common insulating means (e.g., wire insulation, washers,
gaskets, spacers,
bushings, and the like). The conductive tip 111 of the operative element 110
is positioned in
electrical conductive contact with at least one muscle, or at least one nerve,
or at least one
muscle and nerve.
[0079] As shown, the stimulation probe 50 is mono-polar and is equipped with a
single operative
element (i.e., electrode) 110 at the housing proximal end 114. A return
electrode 130, 131 may
be coupled to the stimulation probe 50 and may be any of a variety of
electrode types (e.g.,
paddle, needle, wire, or surface), depending on the surgical procedure being
performed. As
shown, the various return electrodes 130, 131 are coupled to the housing
distal end 118. In an
alternative embodiment, the stimulation device 50 itself may be bipolar by
including a return
electrode in the operative element 110, which precludes the use of a return
electrode coupled to
the stimulation probe 50.
[0080] As shown and described, the stimulation probe 50 may accommodate within
the housing
112 the electrical circuitry of a stimulation control device 22. In this
arrangement, the
stimulation probe 50 may have one or more user operable controls. Two are
shown--155 and
160. Power switch 155 serves a dual purpose of turning the stimulation probe
50 ON and OFF
(or standby), and also can be stepped to control the stimulation signal
amplitude selection within
a predefined range (e.g., 0.5, 2.0, and 20 mA). In this configuration, the
switch may be a four
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position switch. Before the first use of the stimulation probe 50, the power
switch 155 is in the
OFF position and keeps the stimulation probe off. After the stimulation probe
50 has been turned
ON--by moving the switch 155 to an amplitude selection--the OFF position now
corresponds to
a standby condition, where no stimulation would be delivered. In one
embodiment, once the
stimulation probe 50 has been turned on, it cannot be turned off, it can only
be returned to the
standby condition and will remain operational for a predetermined time, e.g.,
at least about seven
hours. This feature is intended to allow the stimulation probe 50 to only be a
single use device,
so it can not be turned OFF and then used again at a later date.
[0081] The pulse control device 160 allows for adjustment of the stimulation
signal pulse width
from a predefined range (e.g., about zero to about 200 microseconds). In one
embodiment, the
pulse control 160 may be a potentiometer to allow a slide control to increase
or decrease the
stimulation signal pulse width within the predefined range.
[0082] The stimulation pulse may have a non-adjustable frequency in the range
of about 10 Hz
to about 20 Hz, and desirably about 16 Hz.
[0083] As a representative example, the stimulation pulse desirably has a
biphasic waveform
with controlled current during the cathodic (leading) phase, and net DC
current less than 10
microamps, switch adjustable from about 0.5 milliamps to about 20 milliamps,
and pulse
durations adjustable from about zero microseconds up to about 200
microseconds. A typical,
biphasic stimulus pulse is shown in FIG. 6.
[0084] The operative element 110 exits the housing 112 at the proximal end 114
to deliver
stimulus current to the excitable tissue. The operative element 110 comprises
a length and a
diameter of a conductive material, and is desirably fully insulated with the
exception of the most
proximal end, e.g. about 1.0 millimeters to about 10 millimeters, and
desirably about 4
millimeters to about 6 millimeters, which is non-insulated and serves as the
stimulating tip or
surface (or also referred to as active electrode) 111 to allow the surgeon to
deliver the stimulus
current only to the intended tissue. The small area of the stimulating surface
111 (the active
electrode) of the operative element 110 ensures a high current density that
will stimulate nearby
excitable tissue. The insulation material 113 may comprise a medical grade
heat shrink.
[0085] The conductive material of the operative element 110 comprises a
diameter having a
range between about 0.5 millimeters to about 1.5 millimeters, and may be
desirably about 1.0
millimeters. The length of the operative element 110 may be about 50
millimeters to about 60
millimeters, although it is to be appreciated that the length may vary
depending on the particular
application. As shown, the operative element 110 may include one or more bends
to facilitate
accurate placement of the stimulating surface 111. In one embodiment, the
conductive material
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of operative element 110 is made of a stainless steel 304 solid wire, although
other known
conductive materials may be used.
[0086] As previously described, in monopolar operation, a return electrode (or
indifferent
electrode) 130 or 131, for example, provides an electrical path from the body
back to the control
device 22 within the housing 112. The return electrode 130 (see FIG. 3A) may
be placed on the
surface of intact skin (e.g., surface electrodes as used for ECG monitoring
during surgical
procedures) or it might be needle-like 131 (see FIGS. 3B and 3C), and be
placed in the surgical
field or penetrate through intact skin. The housing's distal end 118 can
incorporate a connector or
jack 120 which provides options for return current pathways, such as through a
surface electrode
130 or a needle electrode 131, having an associated plug 122. It is to be
appreciated that a return
electrode and associated lead may be an integral part of the stimulation probe
50, i.e., no plug or
connector, as shown in FIG. 3C.
[0087] Additionally, the device 50 may desirably incorporate a visual or audio
indicator 126 for
the surgeon. This visual or audio indicator 126 allows the surgeon to confirm
that the stimulator
50 is delivering stimulus current to the tissue it is contacting. Through the
use of different tones,
colors, different flash rates, etc., the indicator 126 (which can take the
form, e.g., of a light
emitting diode (LED)) allows the surgeon to confirm that the stimulating tip
111 is in place, the
instrument is turned ON, and that stimulus current is flowing. Thus the
surgeon has a much
greater confidence that the failure to elicit a muscle contraction is because
of lack of viable
nervous tissue near the tip 111 of the stimulator 50 rather than the failure
of the return electrode
connection or some other instrumentation problem.
[0088] As a representative example, in use the indicator 126 may be configured
to illuminate
continuously in one color when the stimulation probe 50 is turned on but not
in contact with
tissue. After contact with tissue is made, the indicator 126 may flash (i.e.,
blink) to indicate that
stimulation is being delivered. If the stimulation has been requested, i.e.,
the stimulation probe
has been turned on, but there is no stimulation being delivered because of a
lack of continuity
between the operative element 110 and the return electrode 130, or an
inadequate connection of
the operative element 110 or the return electrode 130 to the patient tissue,
the indicator 126 may
illuminate in a different color, and may illuminate continuously or may flash.
[0089] In one embodiment, as call be best seen in FIGS. 3C and 5, the
indicator 126 comprises a
ring indicator 128 that provides a visual indication around at least a
portion, and desirably all of
the circumference of the stimulation probe 50 generally near the flexible nose
cone 62. The
visual ring indicator 128 may be an element of the gripping portion 60, or it
may be an element
of the flexible nose cone 62, or the ring indicator may positioned between the
gripping portion
60 and the flexible nose cone 62. The ring indicator 128 may also include a
reflective element
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129 to improve and focus the illumination effect of the light emitting source,
e.g., one or more
LEDs. The ring indicator 128 and the reflective element may be a single
component, or more
than one component (as can be seen in FIGS. 5 and 15).
[0090] Audio feedback also makes possible the feature of assisting the surgeon
with monitoring
nerve integrity during surgery. The insulated lead 124 connects to the
operative element 110 that,
in use, is positioned within the surgical field on a nerve distal to the
surgical site. Stimulation of
the nerve causes muscle contraction distally. The stimulation control device
22 incorporated
within the housing 112 may be programmed to provide an audio tone followed by
a stimulation
pulse at prescribed intervals. The audio tone reminds the surgeon to observe
the distal muscle
contraction to confirm upon stimulation that the nerve is functioning and
intact.
[0091] FIG. 15 shows an exploded view of a representative stimulation probe
50. As can be
seen, the stimulation control device 22 is positioned within the housing 112.
A battery 34 is
electrically coupled to the control device 22. A first housing element 90 and
a second housing
element 92 partially encapsulate the control device 22. The ring indicator 128
and the reflective
element 129 are coupled to the proximal end of the housing 112. The operative
element 110
extends through the nose cone 62 and couples to the control device 22.
Desirably, the stimulation
probe 50 will be constructed in a manner to conform to at least the IPX1
standard for water
ingress.
[0092] Alternatively, as FIG. 2 shows, the stimulation control device 22 may
be housed in a
separate case, with its own input/output (I/O) controls 26. In this
alternative arrangement, the
stimulation control device 22 is sized small enough to be easily removably
fastened to a
surgeon's arm or wrist during the surgical procedure, or otherwise positioned
in close proximity
to the surgical location (as shown in FIG. 7), to provide sufficient audio
and/or visual feedback
to the surgeon. In this arrangement, the separate stimulation control device
22 can be temporarily
coupled by a lead to a family of various medical devices for use.
[0093] The present invention includes a method of identifying/locating tissue,
e.g., a nerve or
muscle, in a patient that comprises the steps of providing a hand-held
stimulation probe 50, 100
as set forth above, engaging a patient with the first operative element 110
and the second
electrode 130, moving the power switch 155 to an activation position causing a
stimulation
signal 29 to be generated by the stimulation control device 22 and transmitted
to the first
operative element 110, through the patient's body to the second electrode 130,
and back to the
stimulation control device 22. The method may also include the step of
observing the indicator
126 to confirm the stimulation probe 50, 100 is generating a stimulation
signal. The method may
also include the step of observing a tissue region to observe tissue movement
or a lack thereof.
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B. The Stimulation Control Device
[0094] As FIG. 8 shows, the stimulation control device 22 includes a circuit
32 that generates
electrical stimulation waveforms. A battery 34 desirably provides the power.
The control device
22 also desirably includes an on-board, programmable microprocessor 36, which
carries
embedded code. The code expresses pre-programmed rules or algorithms for
generating the
desired electrical stimulation waveforms using the stimulus output circuit 46
and for operating
the visible or audible indicator 126 based on the controls actuated by the
surgeon.
[0095] In one form, the size and configuration of the stimulation control
device 22 makes for an
inexpensive device, which is without manual internal circuit adjustments. It
is likely that the
stimulation control device 22 of this type will be fabricated using automated
circuit board
assembly equipment and methods.
C. Incorporation with Surgical Devices
[0096] A stimulation control device 22 as just described may be electrically
coupled through a
lead, or embedded within various devices commonly used in surgical procedures
(as previously
described for the stimulation probe 50).
1. Cutting Device
[0097] In FIGS. 9A and 9B, a device 200 is shown that incorporates all the
features disclosed in
the description of the stimulation probe 50, 100, except the device 200
comprises the additional
feature of providing an "energized" surgical device or tool. FIG. 9A shows the
tool to be a
cutting device 200 (e.g., scalpel) removably coupled to a stimulation control
device 22.
[0098] In the embodiment shown, the cutting device 200 includes a body 212
that carries an
insulated lead 224. The insulated lead 224 connects to an operative element,
such as electrode
210, positioned at the body proximal end 214 and a plug-in receptacle 219 at
the body distal end
118. The lead 224 within the body 212 is insulated from the body 212 using
common insulating
means (e.g., wire insulation, washers, gaskets, spacers, bushings, and the
like).
[0099] In this embodiment, the electrode 210 performs the cutting feature
(e.g., knife or razor).
The electrode 210 performs the cutting feature in electrical conductive
contact with at least one
muscle, or at least one nerve, or at least one muscle and nerve. The cutting
device 200 desirably
includes a plug-in receptacle 216 for the electrode 210, allowing for use of a
variety of cutting
electrode shapes and types (e.g., knife, razor, pointed, blunt, curved),
depending on the specific
surgical procedure being performed. In this configuration, the lead 224
electrically connects the
electrode 210 to the stimulation control device 22 through plug-in receptacle
219 and lead 24.
[0100] In one embodiment, the cutting device 200 is mono-polar and is equipped
with a single
electrode 210 at the body proximal end 214. In the mono-polar mode, the
stimulation control
device 22 includes a return electrode 38 which functions as a return path for
the stimulation
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signal. Electrode 38 may be any of a variety of electrode types (e.g., paddle,
needle, wire, or
surface), depending on the surgical procedure being performed. The return
electrode 38 may be
attached to the stimulation device 22 by way of a connector or plug-in
receptacle 39. In an
alternative embodiment, the cutting device 200 may be bipolar, which precludes
the use of the
return electrode 38.
[0101] In the embodiment shown in FIG. 9B, the cutting device 200 accommodates
within the
body 212 the electrical circuitry of the stimulation control device 22. In
this arrangement, the
cutting device 200 may have at least two operational slide controls, 255 and
260. Power switch
255 serves a dual purpose of turning the stimulation signal to the cutting
device 200 on and off,
and also is stepped to control the stimulation signal amplitude selection from
a predefined range
(e.g., 0.5, 2.0, and 20 mA). The pulse control switch 260 allows for
adjustment of the stimulation
signal pulse width from a predefined range (e.g., zero through 200
microseconds).
[0102] At the body distal end 218, a second plug-in receptacle 220 may be
positioned for receipt
of a second lead 222. Lead 222 connects to electrode 230 which functions as a
return path for the
stimulation signal when the cutting device 200 is operated in a mono-polar
mode.
[0103] Additionally, the device 200 may incorporate a visual or audio
indicator for the surgeon,
as previously described.
[0104] The present invention includes a method of identifying/locating tissue,
e.g., a nerve or
muscle, in a patient that comprises the steps of providing cutting device 200
as set forth above,
engaging a patient with the first electrode 210 and the second electrode 230,
moving the power
switch 255 to an activation position causing a stimulation signal 29 to be
generated by the
stimulation control device 22 and transmitted to the first electrode 210,
through the patient's
body to the second electrode 230, and back to the stimulation control device
22. The method
may also include the step of observing the indicator 126 to confirm the
cutting device 200 is
generating a stimulation signal. The method may also include the step of
observing a tissue
region to observe tissue movement or a lack thereof.
2. Drilling Device
[0105] In FIGS. 10A and 10B, a device 300 is shown that incorporates all the
features disclosed
in the description of the stimulation probe 50, 100, except the device 300
comprises the
additional feature of providing an "energized" surgical device or tool, which
comprises a drilling
device 300. In FIG. 10A is drilling device 300 is removably coupled to a
stimulation control
device 22.
[0106] In the embodiment shown, the drilling device 300 includes a body 312
that carries an
insulated lead 324. The insulated lead 324 connects to an operative element,
such as electrode
310, positioned at the body proximal end 314 and a plug-in receptacle 319 at
the body distal end
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318. The lead 324 within the body 312 is insulated from the body 312 using
common insulating
means (e.g., wire insulation, washers, gaskets, spacers, bushings, and the
like).
[0107] In this embodiment, the electrode 310 performs the drilling feature.
The electrode 310
may also perform a screwing feature as well. The electrode 310 performs the
drilling feature in
electrical conductive contact with a hard structure (e.g., bone).
[0108] The drilling device 300 desirably includes a plug-in receptacle or
chuck 316 for the
electrode 310, allowing for use of a variety of drilling and screwing
electrode shapes and sizes
(e.g., 1/4 and 3/8 inch drill bits, Phillips and flat slot screw drivers),
depending on the specific
surgical procedure being performed. In this configuration, the lead 324
electrically connects the
electrode 310 to the stimulation control device 22 through plug-in receptacle
319 and lead 324.
[0109] In one embodiment, the drilling device 300 is mono-polar and is
equipped with a single
electrode 310 at the body proximal end 314. In the mono-polar mode, the
stimulation control
device 22 includes a return electrode 38 which functions as a return path for
the stimulation
signal. Electrode 38 may be any of a variety of electrode types (e.g., paddle,
needle, wire, or
surface), depending on the surgical procedure being performed. The return
electrode 38 may be
attached to the stimulation device 22 by way of a connector or plug-in
receptacle 39. In an
alternative embodiment, the drilling device 300 may be bipolar, which
precludes the use of the
return electrode 38.
[0110] In FIG. 10B, the drilling device 300 is shown to accommodate within the
body 312 the
electrical circuitry of the stimulation control device 22. The drilling device
300 may have at least
two operational slide controls, 355 and 360. Power switch 355 serves a dual
purpose of turning
the stimulation signal to the drilling device 300 on and off, and also is also
stepped to control the
stimulation signal amplitude selection from a predefined range (e.g., 0.5,
2.0, and 20 mA). The
pulse control switch 360 allows for adjustment of the stimulation signal pulse
width from a
predefined range (e.g., zero through 200 microseconds). At the body distal end
318, a second
plug-in receptacle 320 may be positioned for receipt of a second lead 322.
Lead 322 connects to
electrode 330 which functions as a return path for the stimulation signal when
the drilling device
300 is operated in a mono-polar mode.
[0111] Additionally, the device 300 may incorporate a visual or audio
indicator for the surgeon,
as previously described.
[0112] The present invention includes a method of identifying/locating tissue,
e.g., a nerve or
muscle, in a patient that comprises the steps of providing a drilling device
300 as set forth above,
engaging a patient with the first electrode 310 and the second electrode 330,
moving the power
switch 355 to an activation position causing a stimulation signal 29 to be
generated by the
stimulation control device 22 and transmitted to the first electrode 310,
through the patient's
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body to the second electrode 330, and back to the stimulation control device
22. The method
may also include the step of observing the indicator 126 to confirm the
drilling device 400 is
generating a stimulation signal. The method may also include the step of
observing a tissue
region to observe tissue movement or a lack thereof.
3. Pilot Auger
[0113] An additional aspect of the invention provides systems and methods for
controlling
operation of a family of stimulating devices comprising a stimulation control
device electrically
coupled to a pilot auger for hard surface rotary probing.
[0114] This embodiment incorporates all the features disclosed in the
description of the
stimulation probe 50, 100, except this embodiment comprises the additional
feature of providing
an "energized" surgical device or tool. FIG. 11A shows a pilot auger device
400 removably
coupled to a stimulation control device 22. In the embodiment shown, the pilot
auger device 400
includes a body 412 that carries an insulated lead 424. The insulated lead 424
connects to an
operative element, such as an electrode 410, positioned at the body proximal
end 414 and a plug-
in receptacle 419 at the body distal end 418. The lead 424 within the body 412
is insulated from
the body 412 using common insulating means (e.g., wire insulation, washers,
gaskets, spacers,
bushings, and the like). In this embodiment, the electrode 410 performs the
pilot augering
feature. The electrode 410 performs the pilot augering feature in electrical
conductive contact
with a hard structure (e.g., bone).
[0115] The pilot auger device 400 desirably includes a plug-in receptacle or
chuck 416 for the
electrode 410, allowing for use of a variety of pilot augering electrode
shapes and sizes (e.g.,
1/32, 1/16, and 1/8 inch), depending on the specific surgical procedure being
performed. In this
configuration, the lead 24 electrically connects the electrode 410 to the
stimulation control
device 22 through plug-in receptacle 419 and lead 24.
[0116] In one embodiment, the pilot auger device 400 is mono-polar and is
equipped with a
single electrode 410 at the body proximal end 414. In the mono-polar mode, the
stimulation
control device 22 includes a return electrode 38 which functions as a return
path for the
stimulation signal. Electrode 38 may be any of a variety of electrode types
(e.g., paddle, needle,
wire, or surface), depending on the surgical procedure being performed. The
return electrode 38
may be attached to the stimulation device 22 by way of a connector or plug-in
receptacle 39. In
an alternative embodiment, the pilot auger device 400 may be bipolar, which
precludes the use of
the return electrode 38.
[0117] As FIG. 11B shows. the pilot auger device 400 may accommodate within
the body 412
the electrical circuitry of the stimulation control device 22. At the body
distal end 418, a second
plug-in receptacle 420 may be positioned for receipt of a second lead 422.
Lead 422 connects to
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electrode 430 which functions as a return path for the stimulation signal when
the pilot auger
device 400 is operated in a mono-polar mode.
[0118] The pilot auger device 400 includes a power switch 455. When moved to
an activation
position, a stimulation signal is generated by the stimulation control device
22. Additionally, the
device 400 may incorporate a visual or audio indicator for the surgeon, as
previously described.
[0119] The present invention includes a method of identifying/locating tissue,
e.g., a nerve or
muscle, in a patient that comprises the steps of providing a pilot auger
device 400 as set forth
above, engaging a patient with the first electrode 410 and the second
electrode 430, moving the
power switch 455 to an activation position causing a stimulation signal to be
generated by the
stimulation control device 22 and transmitted to the first electrode 410,
through the patient's
body to the second electrode 430, and back to the stimulation control device
22. The method
may also include the step of observing the indicator 126 to confirm the pilot
auger device 400 is
generating a stimulation signal. The method may also include the step of
observing a tissue
region to observe tissue movement or a lack thereof
D. Incorporation with Fixation Devices
[0120] An additional aspect of the invention provides systems and methods for
controlling
operation of a family of stimulating devices comprising a stimulation control
device electrically
coupled to a fixation device or a wrench or screwdriver for placing the
fixation device. A
fixation device (e.g., orthopedic hardware, pedicle screws) is commonly used
during spinal
stabilization procedures (fusion), and internal bone fixation procedures.
[0121] This embodiment incorporates all the features disclosed in the
description of the
stimulation probe 50, 100, except this embodiment comprises the additional
feature of providing
an "energized" fixation device or tool. FIG. 12A shows a fixation device 500
removably coupled
to a stimulation control device 22. In the embodiment shown, the fixation
device 500 includes a
rectangularly shaped body 512 that also serves as an operative element, such
as electrode 510.
The fixation device 500 may take on an unlimited number of shapes as necessary
for the
particular procedure taking place. Pedicle screws 535 may be used to secure
the fixation device
to the bony structure. The electrode 510 performs the fixation feature in
electrical conductive
contact with a hard structure (e.g., bone).
[0122] The fixation device 500 or wrench or screwdriver for placing the
fixation device
desirably includes a plug-in receptacle 519. The fixation device 500 may take
on an unlimited
variety of shapes and sizes depending on the specific surgical procedure being
performed. In this
configuration, the lead 24 electrically connects the electrode 510 to the
stimulation control
device 22 through plug-in receptacle 519.
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[0123] In one embodiment, the fixation device 500 is mono-polar and is
equipped with the single
electrode 510. In the mono-polar mode, the stimulation control device 22
includes a return
electrode 38 which functions as a return path for the stimulation signal.
Electrode 38 may be any
of a variety of electrode types (e.g., paddle, needle, wire, or surface),
depending on the surgical
procedure being performed. The return electrode 38 may be attached to the
stimulation device 22
by way of a connector or plug-in receptacle 39. In an alternative embodiment,
the fixation device
500 may be bipolar, which precludes the use of the return electrode 38.
[0124] In yet an additional alternative embodiment (see FIG. 12B), the
fixation device may be a
pedicle screw 535. The pedicle screw 535 is removably coupled to a stimulation
control device
22. In the embodiment shown, the pedicle screw 535 includes a head 570 and a
shaft 572, which
both serve as an operative element, such as electrode 574. The electrode 574
performs the
fixation feature in electrical conductive contact with a hard structure (e.g.,
bone), as the pedicle
screw 535 is being positioned within a bony structure. The lead 24
electrically connects the
electrode 574 to the stimulation control device 22, through a break-away
connection or other
similar electrical connective means. The fixation device 535 may take on an
unlimited variety of
shapes and sizes depending on the specific surgical procedure being performed.
[0125] In the mono-polar mode, the stimulation control device 22 includes a
return electrode 38
which functions as a return path for the stimulation signal. Electrode 38 may
be any of a variety
of electrode types (e.g., paddle, needle, wire, or surface), depending on the
surgical procedure
being performed. In an alternative embodiment, the fixation device 500 may be
bipolar, which
precludes the use of the return electrode 38.
[0126] The present invention includes a method of identifying/locating tissue,
e.g., a nerve or
muscle, in a patient that comprises the steps of providing a fixation device
500 as set forth above,
engaging a patient with the first electrode 510 and the second electrode 38,
turning power on to
the stimulation control device 22 through the I/0 controls 26, causing a
stimulation signal 29 to
be generated by the stimulation control device 22 and transmitted to the first
electrode 510,
through the patient's body to the second electrode 38, and back to the
stimulation control device
22. The method may also include the step of observing the indicator 126 to
confirm the fixation
device 500 is generating a stimulation signal. The method may also include the
step of observing
a tissue region to observe tissue movement or a lack thereof.
IV. Technical Features
[0127] The stimulation control device 22, either alone or when incorporated
into a stimulation
probe or surgical device, can incorporate various technical features to
enhance its universality.
A. Small Size
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[0128] According to one desirable technical feature, the stimulation control
device 22 can be
sized small enough to be held and used by one hand during surgical procedures,
or to be installed
within a stimulation probe or surgical device. The angle of the stimulating
tip facilitates access to
deep as well as superficial structures without the need for a large incision.
Visual and/or audible
indication incorporated in the housing provides reliable feedback or status to
the surgeon as to
the request and delivery of stimulus current.
[0129] According to an alternative desirable technical feature, the
stimulation control device 22
may also be sized small enough to be easily removably fastened to a surgeon's
arm or wrist
during the surgical procedure, or positioned in close proximity to the
surgical location (as shown
in FIG. 7), to provide sufficient audio and/or visual feedback to the surgeon.
B. Power Source
[0130] According to one desirable technical feature, power is provided by one
or more primary
batteries 34 for single use positioned inside the housing and coupled to the
control device 22. A
representative battery 34 may include a size "N" alkaline battery. In one
embodiment, two size
"N" alkaline batteries in series are included to provide a 3 volt power
source. This configuration
is sized and configured to provide an operating life of at least seven hours
of operation--either
continuous or intermittent stimulation.
C. The Microprocessor/Microcontroller
[0131] According to one desirable technical feature, the stimulation control
device 22 desirably
uses a standard, commercially available micro-power, flash programmable
microcontroller 36.
The microcontroller 36 reads the controls operated by the surgeon, controls
the timing of the
stimulus pulses, and controls the feedback to the user about the status of the
instrument (e.g., an
LED with 1, 2, or more colors that can be on, off, or flashing).
[0132] The microcontroller operates at a low voltage and low power. The
microcontroller send
low voltage pulses to the stimulus output stage 46 that converts these low
voltage signals into the
higher voltage, controlled voltage, or controlled current, stimulus pulses
that are applied to the
electrode circuit. This stimulus output stage 46 usually involves the use of a
series capacitor to
prevent the presence of DC current flow in the electrode circuit in normal
operation or in the
event of an electronic component failure.
V. Representative Use of a Stimulation Probe
[0133] The stimulation probe 50, 100, as described, make possible the
application of a
stimulation signal at sufficiently high levels for the purposes of locating,
stimulating, and
evaluating nerve or muscle, or both nerve and muscle integrity in numerous
medical procedures,
including, but not limited to, evaluating proximity to a targeted tissue
region, evaluating
proximity to a nerve or to identify nerve tissue, evaluating if a nerve is
intact (i.e., following a
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traumatic injury) to determine if a repair may be needed, evaluating muscle
contraction to
determine whether or not the muscle is innervated and/or whether the muscle is
intact and/or
whether the muscle is severed, and evaluating muscle and tendon length and
function following a
repair or tendon transfer prior to completing a surgical procedure.
[0134] Instructions for use 80 are desirably included in a kit 82 along with a
stimulation probe
50. The kit 82 can take various forms. In the illustrated embodiment, kit 82
comprises a sterile,
wrapped assembly. A representative kit 82 includes an interior tray 84 made,
e.g., from die cut
cardboard, plastic sheet, or thermo-formed plastic material, which hold the
contents. Kit 82 also
desirably includes instructions for use 80 for using the contents of the kit
to carry out a desired
therapeutic and/or diagnostic objectives.
[0135] The instructions 80 guide the user through the steps of unpacking the
stimulation probe
50, positioning the electrodes, and disposing of the single use disposable
stimulator 50.
Representative instructions may include, but are not limited to:
(1) Remove the stimulation probe 50 from sterile package 88.
(2) Remove cover 94 (e.g., a silicone cover) from the operative element 110.
(3) Remove protective cover 86 from the return electrode 131.
(4) Position the return electrode 131 in contact with the patient such that:
(a) The return electrode is desirably positioned in an area remote from the
area to
be stimulated;
(b) The return electrode is desirably not positioned across the body from the
side
being stimulated; and
(c) The return electrode is desirably not in muscle tissue.
(5) Turn the stimulation probe 50 ON by moving the power switch 155 from OFF
to the 0.5
mA setting (or greater).
(6) The stimulation probe 50 desirably is turned ON before the operative
element 110 makes
contact with tissue.
(7) The indicator 126 will be illuminated yellow (for example) continuously if
the
stimulation probe 50 is ON, but not in contact with tissue.
(8) Contact tissue with the operative element 110.
(9) Adjust the pulse control 160 gradually to increase the level of
stimulation.
(10) The indicator 126 will flash yellow indicating that stimulation is
being delivered.
(11) A flashing red (for example) indicator 126 means that stimulation
has been
requested, but no stimulation is being delivered because of inadequate
connection of the
operative element 110 or the return electrode 131 to the patient tissue.
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(12) Check the return electrode contact and position, and check the
operative element
110 contact and position.
(13) Placing the power switch 155 to the off/standby position will stop
stimulation and
the visual indictor 126 will be illuminated yellow continuously.
(14) Placing the pulse control 160 at the minimum position will stop
stimulation and
the visual indictor 126 will be illuminated yellow continuously.
(15) A low/depleted battery 34 will cause the stimulation probe 50 to
automatically
turn OFF and the visual indicator 126 will not be illuminated.
(16) No further use of the stimulator 50 will be possible.
(17) At end of use, move the power switch 155 to the off/standby position
and move
the pulse control 160 to the minimum position.
(18) Cut off and dispose of the return electrode 131 in an appropriate
sharps/biohazard
container.
(19) Dispose of the stimulation probe 50 per hospital or facility
guidelines.
[0136] In an embodiment shown in FIGS. 16-22, the system may include a bipolar
stimulation
device as described further below.
The System
[0137] FIG. 16 shows a system 610 for differentiating and/or identifying
within a tissue region
TR the presence of a targeted nerve fiber or branch. The system 610 includes a
first system 612
for generating and applying a stimulation current to tissue in the region TR
of the targeted nerve
fiber or branch. The system 610 also includes a second system 614 for sensing
the presence or
absence of an anticipated physiologic response to the application of the
electrical stimulation
current. The presence of the anticipated physiologic response differentiates
andlor identifies
within a tissue region TR the presence of a targeted nerve fiber or branch.
Once differentiated
and identified, the targeted nerve fiber or branch can be manipulated for
desired diagnostic
and/or therapeutic reasons.
A. The First Device
[0138] As FIG-S. 17A to 19 show, the first system 612 includes a handle 616,
which is preferably
sized small enough to be held and used like a flashlight or screwdriver,
allowing the thumb to
push a button to control the application of stimulus current (see FIG. 19).
The handle 616 carries
an insulated probe 618. The probe 618 carries, at its distal end, an electrode
assembly 620 (see
FIG. 18A). The first system 612 is preferably a sterile, single use
instrument.
[0139] In a representative embodiment, the handle 616 is cylindrical in shape
and has a
maximum diameter at its proximal end of about 25 mm. The handle 616 tapers
from proximal
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end to distal end to a lesser diameter of about 10 mm. In a representative
embodiment, the length
of the handle 616 is about 17 cm.
[0140] In a representative embodiment, the probe 618 extends about 8 cm from
the distal end of
the handle 616 and includes an electrode assembly 620 at its distal end. In a
representative
embodiment, the probe 618 has a diameter of about 10 mm.
[0141] The electrode assembly 620 (see FIG. 18A) is sized and configured for
accurate
identification of tissue regions innervated by targeted nerves. The electrode
assembly 620 may
be configured to resemble something like a dental mirror and may have a
diameter in the range
of about 10 mm to about 15 mm. The assembly 620 may be somewhat offset (e.g.,
10 degrees to
50 degrees), from the probe 618 to provide ease of use and a more ergonomic
configuration. The
electrode assembly 620 may comprise a bipolar array of two contacts 622 and
624 exposed on
the distal face 626 of the probe 618. The contacts 622 and 624 may have a
diameter in the range
of about 1 (one) mm to about 3 mm and may project off the distal face by 1
(one) mm or less.
The spacing between the contacts 622 and 624 on the distal face 626 may be
about 1 (one) mm
to about 4 mm. The edges of the contacts 622 and 624 are desirably rounded, so
as not to injure
tissue. The small area of the contacts 622 and 624 ensures a high current
density that will
stimulate nearby excitable tissue.
[0142] It is to be appreciated that other configures for an electrode assembly
may be possible.
For example, FIGS. 18B and 18C show two additional possible configurations.
FIG. 18B shows
an electrode assembly 640 having contacts 642 and 644 exposed on the distal
face 646 of the
probe 618. The contacts 642 and 644 are circumferentially spaced 180-degrees
apart. As shown,
the contacts 642 and 644 are exposed on the distal face 646 of the probe 618,
each occupying
about 90-degrees to about 95-degrees of the circumference of the distal face
646 of the probe
618. The contacts 642 and 644 also desirably extend proximally along the probe
for about 5 mm,
as well as project a short distance beyond the distal face 646 of the probe
618, e.g., 1 mm.
Spacing between the contacts 642 and 644 on the distal face 646 may be about 1
(one) mm to
about 4 mm. The edges of the contacts 642 and 644 are desirably rounded, so as
not to injure
tissue. FIG. 3C shows a ring electrode assembly having an outer contact 652
and an inner contact
654 exposed on the distal face 656 of the probe 618. The outer contact 652 may
also extend
proximally along the probe.
[0143] The contacts 622 and 624 (and their alternative embodiments) can
comprise, e.g.,
stainless steel, silver, platinum, or platinum treated with platinum black.
The probe 618
comprises, especially at its distal face 626, a plastic material that is
preferably poorly wetted by
blood, saline, and body fluids, so as to minimize the risk of passing current
through the fluid
pathway when direct tissue contact is not present. The probe 618 is insulated
from the handle
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616 using common insulating means (e.g., wire insulation, washers, gaskets,
spacers, bushings,
and the like).
[0144] Alternatively, a monopolar arrangement can be used. In this
arrangement, a return
electrode (or indifferent electrode) must be provided to provide an electrical
path from the body
back to the instrument. The return electrode may be placed on the surface of
intact skin (e.g.,
surface electrodes, such as used for ECG monitoring during surgical
procedures) or it might be
needle-like and be placed in the surgical field or penetrate through intact
skin.
[0145] An electrical stimulation control circuitry 628 is carried within the
handle 616 (see FIGS.
17A and 17B). The control circuitry 628 generates a stimulation current which
is applied through
the contacts 622 and 624. The control circuitry 628 is powered by a primary
battery (for single
use applications) located within the handle 616. If the instrument is not
intended for single use,
the battery can be rechargeable.
[0146] The control circuitry 628 desirably includes an on-board, programmable
microprocessor,
which carries embedded code. The code expresses pre-programmed rules or
algorithms for
generating the desired electrical stimulation waveforms. In a representative
embodiment, the
stimulus frequency is 20 Hz, (although the frequency may be adjustable, e.g.,
3 Hz to 100 Hz),
and the waveform comprises a charge balanced biphasic waveform (i.e., no net
DC current
flow).
[0147] Other operating parameters of the control circuitry 628 can be
regulated by controls
conveniently carried on the handle 616.
[0148] In the illustrated embodiment (see FIG. 17A), stimulus amplitude and
the stimulus pulse
duration are adjusted by a rotary switch 630 or wheel near or on the proximal
end of the handle
616. The rotary control switch 630 desirably has labeling to identify multiple
setting options. For
example, the first few settings may include different amplitudes each with the
same fixed pulse
duration. Additional settings may provide a range of selectable settings that
include specific
combinations of amplitudes and pulse durations. The rotary control switch 630
also desirably has
detents that gives the clinician good tactile feedback when moving from one
setting to the next.
The range of stimulus settings labeled can comprise, e.g., OFF, STANDBY, 1.5
mA at 100 sec,
3 mA at 100 sec, 5 mA at 100iasec, 5 mA at 300 sec, and 10 mA at 500 g.sec.
[0149] A momentary pushbutton 632, e.g., on the side of the housing 616, e.g.,
for access by a
thumb, controls the delivery of the stimulation current through the contacts
622 and 624. The
momentary pushbutton 632 allows the first system 612 to be controlled, e.g.,
stimulation current
to be turned on and off, with only one hand. The stimulus current is delivered
(at the
amplitude/duration set by the rotary switch 630) through the contacts 622 and
624 only if the
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momentary pushbutton 632 is depressed. If the pushbutton 632 is not depressed,
no stimulus
current is delivered.
[0150] In an alternative embodiment (see FIG. I 7B), the stimulus pulse
duration may be
regulated by an adjustable stepped slide switch 634 on the handle 616. Thus,
if the momentary
pushbutton 632 is depressed, stimulus current is applied at the regulated
amplitude and regulated
duration. If the pushbutton 632 is not depressed, no stimulus current is
delivered. The slide
switch 634 desirably has labeling to identify the pulse duration selected. The
slide switch 634
also desirably has detents that gives the clinician good tactile feedback when
moving from one
pulse duration level to the next. The range of pulse duration settings labeled
can comprise, e.g.,
OFF, 100 pec, 300 sec, or 500 sec. The slide switch 634 could also have a
STANDBY
position labeled.
[0151] Alternatively, if the pulse duration slide switch 634 is not provided,
and the pulse
duration is not selected via the rotary control switch 630, the stimulus pulse
durations can be
fixed at a nominal selected duration, e.g., 250 IASCC.
[0152] The control circuitry 628 desirably includes a light indication, i.e.,
a light emitting diode
LED 638 on the handle, that provides various indications to the clinician. For
example, the LED
638 may confirm battery status and stimulator ON/OFF states. Also desirably,
the LED 638 may
flash green when adequate stimulus is being delivered, and flash red when
inadequate stimulus is
delivered. In addition, the LED 638 may flash or illuminate only if the
current actually delivered
is within a desired percentage of the requested amplitude, e.g., within 25% of
the requested
value. The control circuitry 628 thereby provides reliable feedback to the
clinician as to the
requested delivery of stimulus current.
[0153] in an alternative embodiment, the control circuitry 628 may also
generate an audio tone
only when the stimulus current is being delivered. The tone is transmitted by
an indicator 636 on
the handle 616.
[0154] Through the use of different tones, colors, different flash rates,
etc., the control circuitry
628 can allow the clinician to confirm that the probe is in contact with
tissue, the instrument is
turned ON, the battery has sufficient power, and that stimulus current is
flowing. Thus the
clinician has a much greater confidence that the failure to elicit a desired
response is because of
lack of viable nervous tissue near the tip of the probe rather than the
failure of the return
electrode connection or some other instrumentation problem.
B. The Second Device
[0155] The second system 614 can take various forms, depending upon the
physiologic function
of the targeted tissue region and the nature and character of the physiologic
response anticipated
due to the application of the electrical stimulation current by the first
system 612.
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[0156] For example, the electrical stimulation of parasympathetic nerves
affecting a respiration
activity causes breathing to slow. Therefore, when it is desired to
differentiate and/or identify the
presence or absence of parasympathetic nerves affecting a respiration
activity, a reduction in the
breathing rate can be used as the anticipated physiologic response. In this
arrangement, the
second system 614 can comprise an instrument that monitors breathing. The
instrument can
comprise, e.g., a chest position sensor and a spirometer box that monitor
movements of the chest.
The instrument can also comprise a breathing sensor, which is worn around the
chest, such as a
breathing (stretch) sensor or a stethograph. A decrease in breathing rate
detected by the second
device indicates that the first device is located at or near parasympathetic
nerves.
[0157] As another example, the stimulation of parasympathetic nerves affecting
heart function
increases the resting potential and decreases the rate of diastolic
depolarization. Under these
circumstances the heart rate slows. Therefore, when it is desired to
differentiate and/or identify
the presence or absence of parasympathetic nerves affecting heart activity,
the heart rate can be
used as the anticipated physiologic response. In this arrangement, the second
system 614 can
comprise an electrocardiography (EKG) instrument.
[0158] As another example, the stimulation of parasympathetic nerves affecting
digestion (e.g.,
during the cephalic phase of gastric secretion) mediates reflex gastric
secretion. Therefore, when
it is desired to differentiate and/or identify the presence or absence of
parasympathetic nerves
affecting stomach activity, the reduction in the secretion of gastric juice
can be used as the
anticipated physiologic response. In this arrangement, the second system 614
can comprise
instrumentation that senses the secretion of gastric juice.
[0159] As another example, the second system. 614 can comprise an
electromyography (EMG)
instrument. The EMG instrument measures nerve impulses within muscles. The EMG
system
includes electrodes that are placed in the muscles in the tissue region
innervated with
parasympathetic nerves, and the electronic responses to operation of the first
system 612 can be
observed using an instrument that displays movement of an electric current
(e.g., an
oscilloscope). As muscles contract, they emit a weak electrical signal that
can be detected,
amplified, and tracked as the anticipated physiologic response.
Use of the System
[0160] In use, the first system 612 is positioned in contact with tissue in a
targeted tissue region
TR. A clinician may operate the first system 612 with one hand to apply the
stimulation current.
The clinician's other hand can then be used to make adjustments to the
stimulation current as
necessary. The second system 614 monitors the physiologic response. The first
system 612 is
located and relocated (if necessary) until the monitored physiologic response
indicated by the
second system 614 matches or approximates the anticipated physiologic
response. This indicates
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the presence of the targeted nerve fiber or branch, and the identified
location may then be
marked. A desired treatment regime can then be performed, e.g., to manipulate
the
parasympathetic nervous system for therapeutic benefit.
[0161] For example, it has been observed that the parasympathetic nervous
system of the heart
can be manipulated to coordinate cardiac conduction and/or function as relates
to atrial
fibrillation, without tissue ablation and without interrupting physiologic
conduction. It is known
that parasympathetic nerve fibers of the vagus nerve can be manipulated to
affect atrial cycle
length. It is also known that parasympathetic nerve fibers of the vagus nerve
selectively
innervate the epicardial antrioventricular (AV) node fat pad and the
sinoatrial (SA) node fat pad
(as FIG. 20 shows).
[0162] The system. 610 makes possible, e.g., the differentiation and
identification of the
epicardial AV node fat pad on the surface of the heart, and thereby makes it
possible to access
the parasympathetic nervous system of the heart at this location for
therapeutic benefit.
[0163] More particularly, the first system 612 of the system 610 makes
possible the application
highly localized electrical stimulation on the surface of the heart, while the
second system 614
monitors heart rate. The clinician may start the application of the stimulus
current at the lowest
amplitude setting, and increase the amplitude setting as necessary.
Adjustments may be
necessary due to the physiological differences of tissue regions from patient
to patient. The
clinician may also start the application of the stimulus current at something
other than the lowest
amplitude setting after a visual inspection of the tissue region TR indicates
that a higher initial
setting may be necessary.
[0164] When the first system 612 is applying stimulation and is ultimately
located at or near the
region of the AV node fat pad (see FIG. 22), the heart rate (monitored by the
second system 614,
e.g., an EKG instrument) will decrease. An EKG instrument 614 will indicate a
decrease in heart
rate by an increase in the R-to-R interval observed on EKG (compare the R-to-
R. interval shown
in FIG. 21 to the increased R-to-R interval shown in FIG. 22). The clinician
may then stop the
application of stimulation current to the tissue region, e.g., the identified
AV node fat pad, and
observe an increase in the heart rate returning to the original heart rate (a
decrease in the R-to-R
interval observed on EKG). The clinician may go through the steps of applying
stimulation
current, observing an increase of the R-to-R interval, stopping the
application of stimulation
current, and observing a decrease in the R-to-R interval, to confirm the
accurate location of the
targeted tissue region, e.g., the AV node fat pad. In this way, the system 610
allows a clinician to
systematically and accurately locate the AV node fat pad (and other regions
selectively
innervated by parasympathetic nerves) on the surface of the heart.
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[0165] Once located, the clinician may use the first system 612 to apply a die
or other marker to
maintain identification of the AV node fat pad. Alternatively, a separate
applicator may be used
to apply a die or other marker, or, the clinician may use visual skills along
with their finger, for
example, to maintain identification of the AV node fat pad. The clinician can
then take steps to
perturb the parasympathetic nervous system of the heart for therapeutic
benefit. For example, by
either electrical or non-electrical manipulation of the AV node fat pad
located by the system 610,
the clinician can treat or prevent uncontrolled atrial fibrillation or perform
other desired
therapies, or the clinician can apply closed-loop feed-back control algorithms
that provide
physiologic control of AV nodal rate.
[0166] Manipulation of the AV node fat pad located by the system 610 preserves
physiologic
conduction. With electrical manipulation, its beneficial effects can be turned
on and turned off
instantaneously, and without attenuation of effect. Manipulation of the AV
node fat pad may
provide a viable alternative to AV node ablation in the treatment of atrial
fibrillation, which does
not preserve physiologic conduction and instead consigns patients to pacemaker
dependency.
Adapter Designs
[0167] in an embodiment, the system 20 may be configured to receive an
adapter. The adapter
may be configured to connect to a portion of the system 20, such as to a
stimulation probe 50.
The adapter may provide additional fitnctionality, usability, and control of
the stimulation probe
50.
[0168] In an embodiment, the adapter may be a bipolar adapter 710, as shown in
FIGS. 23-29.
The adapter may be configured to attach to a control device 22, such as a
stimulation probe 50,
to allow the device to function as a bipolar device, having all the
functionality of the bipolar
device described above.
[0169] The bipolar adapter 710 may be used with a monopolar stimulation device
to provide
more precise stimulation control. Specifically, the bipolar adapter 710 may
provide a return
element 716, in addition to the primary operative element 110 of the
stimulation probe 50, to
constrain the stimulation electrical field and direct stimulation to a
specific desired location, such
as target nerve. The return element 716 may comprise a wire or any other
insulated electrical
conductor and may include a tip or electrode 718 for making electrical contact
with a target
tissue.
[0170] In an embodiment, the adapter 710 may include a connector 712. The
connector 712 may
be any appropriate size and shape, such as generally elongated as shown in
FIG. 23 and 24. The
connector 712 may be generally tapered so as not to obstruct a user's view
during a procedure.
The connector 712 may be configured to connect to the stimulation probe 50.
For example, the
connector may include an opening 714 to receive a portion of the operative
element 110 of the
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stimulation probe 50 therein. The opening 714 may extend through a portion or
the entirety of
the connector 712. The opening 714 may be sized and shaped to receive the
operative element
110 therein. For example, the operative element 110 may extend through the
opening from a first
end of the connector 712 and protrude through the opening 714 at the second or
opposite end of
the connector 712. A conductive portion of the operative element 110 may be
exposed to allow
electrical current to flow to the target tissue.
[0171] The opening 714 may be configured to bold the operative element 110 in
place. For
example the opening 714 may be tapered to hold the probe in a compression fit.
The opening 714
may further be configured to include a set screw or other retaining feature to
maintain the
operative element 110 at the desired location.
[0172] The connector 712 may include the second probe or return element 716.
As shown in
FIG. 25, the return operative element 716 may be spaced apart a specified
distance D from the
opening 714. The distance D may be measured from the center of the opening 714
to the center
of the return element 716, and may be any appropriate distance, such as 2
millimeters, 1
millimeter, or any other appropriate distance.
[0173] The return element 716 may be any appropriate diameter. For example,
the stimulation
probe 50 operative element 110 may have a diameter of approximately 0.04
inches. The return
element 716 may have a smaller diameter, such as 0.02 inches, or any other
appropriate
diameter.
[0174] The bipolar adapter 710 may further include a pigtail wire 720
extending from the
connector 710. The pigtail 720 may be any appropriate length and may be
configured to be
electrically tied to ground or any appropriate circuit. For example, the
pigtail 720 may include a
connector 722 at one end to receive luer connection or other electrical
connection.
[0175] In an embodiment illustrated in FIG. 26, the connector 712 may be
configured to directly
receive an electrical connection from a return operative element. For example,
the connector 712
may include a plug 724 adjacent to the opening 714 to receive the operative
element 110. The
plug 724 may receive a luer connector or any other appropriate electrical
connection. The plug
724 may be in electrical connection with the return element 716.
[0176] In an embodiment, the bipolar adapter 710 may be arranged to clip or
snap onto the
stimulation probe 50. The adapter 710 may include a return element 716 having
an insulated
portion 730 and an exposed portion 732. The adapter 710 may further include
one or more clips
to connect the return element 716 to the stimulation probe 50. For example, as
illustrated in FIG.
27, the adapter 710 may include a first clip 734 arranged to connect to the
body or housing of the
stimulation probe 50. Additional clips 736 may be arranged to connect to the
operative element
110 of the stimulation probe 50. The additional clips 736 may allow the return
element 716 to
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follow the path of the operative element 110 to prevent any obstruction of
users sight lines. The
adapter 710 may include a receptacle 738 connected to the return element 716.
The receptacle
738 may be configured to receive an electrical connector, such as a luer
connection, to provide a
ground or other electrical signal on the return element 716.
[0177] In an embodiment, the adapter 710 may include a single unitary clip
740, as shown in
FIGS. 28 and 29. The unitary clip 740 may be designed to receive both the
return element 716 of
the adapter and the operative element 110 of the stimulation probe 50.
[0178] The unitary clip 740 may include a first channel 742 and a second
channel 744. The first
channel 742 may be configured to receive the primary operative element 110
therein, and the
second channel 744 may be configured to receive the return element 716
therein. The channels
may be generally rounded or having a generally circular or semi-circular cross-
section, or any
appropriate shape to hold and retain the elements 110, 716. The channels may
have different
diameters to accommodate different diameters of the electrodes 110, 716. For
example, the first
channel 742 may be configured to receive an element having a diameter of
approximately 0.04
inches while the second channel may be configured to receive an element having
a diameter of
approximately 0.02 inches. The channels 742, 744 may be different lengths, as
shown in FIGS.
28 and 29. For example, the first channel 742 may be longer and extend to the
base of the
operative element 110, while the second channel 744 may be shorter and may
allow the return
element 716 to extend away from the body of the stimulation probe 50.
[0179] The operative element 110 may be positioned in the first channel 742
such that a tip 111
of the operative element 110 extends beyond an end of the unitary c1ip740.
Likewise, the return
operative element 716 may be positioned in the second channel 744 such that
the tip 718 of the
return operative element 716 extends beyond an end of the unitary clip 740.
[0180] The unitary clip 740 may be bent or angled. For example, as shown in
FIGS. 28 and 29,
the unitary clip may include a first portion 750 and a bent portion 752 angled
away from the first
portion. The angle of the bent portion 752 may be designed to follow and match
an angle of the
operative element 110. The bent portion 752 may be angled downward with
respect to a user
holding the stimulation probe 50 to prevent any visual obstructions and allow
the user to
maintain a clear line of sight.
[0181] The adapter 710 may include a receptacle 746 connected to the return
operative element
716. The receptacle 746 may be configured to receive an electrical connection
therein, such as a
needle or luer connector. The receptacle 746 may allow the return operative
element 716 to be
connected to electrical ground or to complete the electrical circuit of the
stimulation probe 50.
[0182] The clip described in any of the above embodiments may be adjustable.
For example, the
clip may be malleable, slideable, or otherwise moveable to allow the distance
between the
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operative element tip 111 and the return element tip 718 to be selectively
adjusted. The user may
adjust the clip to achieve the desired distance for a given application.
[0183] In an embodiment, the adapter may be a percutaneous adapter 810, as
shown in FIG. 30.
The percutaneous adapter 810 may be configured to allow a stimulation probe 50
to deliver a
stimulation sipial below the skin of a subject patient.
[0184] The percutaneous adapter 810 may include a connector 812. The connector
812 may be
configured to connect to the operative element 110 of a stimulation probe 50.
For example, the
connector may include an opening 814 to receive the operative element 110
therein. The opening
814 may be tapered to maintain the operative element 110 in a compression fit
within the
connector 812. The connector may further include other retaining features,
such as a set screw or
clasp, to retain the connection between the connector 812 and the operative
element 110.
[0185] The percutaneous adapter 810 may include a lead wire 816 extending from
the connector
812. The lead wire 816 may be an electrical conductor in electrical connection
with an operative
element 110 inserted into the connector 812. The lead wire 816 may be any
appropriate length,
such as 24 inches or an length between 12 inches and 48 inches. The lead wire
may further be
any appropriate gauge, such as 24 AWG wire.
[0186] The percutaneous adapter 810 may include a needle 820 connected to the
lead wire 816.
The needle may be made of any appropriate material, such as stainless steel.
Preferable, the
needle may be made of an. electrically conductive material and be in
electrical communication
with the lead wire 816. The hub 822 may be positioned at the base of the
needle 820 to secure
the connection between the lead wire 816 and the needle 820. A portion of the
needle 820 may
be insulated. For example, the needle may be insulated up to 5 millimeters
away from its tip 824.
The exposed tip 824 of the needle 820 may deliver an electrical stimulation
signal to target tissue
below the surface of the skin.
[0187] The foregoing is considered as illustrative only of the principles of
the invention.
Furthermore, since numerous modifications and changes will readily occur to
those skilled in the
art, it is not desired to limit the invention to the exact construction and
operation shown and
described. While the preferred embodiment has been described, the details may
be changed
without departing from the invention, which is defined by the claims.
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